Wireless communication protocols are increasingly used in industrial, commercial, and consumer applications. For example, near-field communication (NFC) is a type of wireless communication that connects electronic devices when they are in close proximity; normally within 10 cm. NFC involves an ‘initiator’ that generates a radio frequency (RF) field to power a passive ‘target’ via electromagnetic induction. Once the target is powered, the initiator is able to request information from the target and perform transactions.
NFC's short-range and ability to power a passive target make NFC advantageous for certain applications. For example, NFC can be used when it is desirable to communicate wirelessly with small unpowered devices. Because the initiator may provide power to the target, NFC targets can have very simple forms, such as unpowered tags, stickers, key fobs, or cards. Moreover, NFC can be used to exchange sensitive and personal information, such as credit or debit card information. Because NFC only operates in short-ranges, NFC prevents man-in-the-middle or similar spoofing attacks. Therefore, NFC does not require authentication steps and demands only simple hardware, providing quick and simple wireless communication. These advantages make NFC a good candidate for contactless applications, such as contactless payment and contactless identification.
While NFC has important advantages, it also has drawbacks that have discouraged user adoption. NFC users complain that NFC may be unreliable, reporting that NFC channels are difficult to establish and often slow. For example, NFC users report they must wait several seconds before an NFC connection between the initiator terminal and their target devices is established. Also, NFC users report that they have to reposition their devices multiple times before the NFC connection is successful, making a transaction that is normally fast unnecessarily cumbersome. In addition, NFC users report that many times after establishing connection, the NFC communication is nonetheless unsuccessful and they must restart the communication process. These reliability issues frustrate users of contactless payment and contactless identification methods, who may then return to traditional non-NFC identification or payment methods to avoid these issues.
Underlying many of these NFC's reliability issues are NFC's requirements of close proximity and tight alignment between the initiator and the target. To have successful and reliable communication, NFC requires that the initiator and the target be within a few centimeters and be precisely aligned. Specifically, NFC coils of the initiator and target should be close and aligned. Without such proper alignment, the energy transfer required to power the target device may be insufficient and/or the communication signals may be obfuscated by noise sources. Indeed, poor alignment between the initiator and target can be catastrophic for the communication because small position or orientation differences can reduce the intensity of RF signals by orders of magnitude. In addition, aligning coils of target device and initiator terminal can be difficult because in many target devices the inductive coil only covers a specific area of the target. For example, while some smartphones have coils covering the full smartphone case, other smartphones have the NFC coil only in a portion of case. Similarly, some credit cards have small coils located only in a specific portion of the card. These variations in the position of coils within the target devices exacerbate misalignment issues because users are forced to attempt multiple orientations of the device before the NFC link can be established.
The disclosed apparatus and methods for wireless communication address one or more of the problems set forth above and/or other problems in the prior art.